Proper Vandal's Script
"bullet" is a property that you should put on all your projectiles, that way your weapons will not track to the projectiles being added. all of your projectiles should have this property, only because the weapons behave very odd when they track to the bullets being fired. "target" is the name of the object that that the guns track to.

It essentially works like this:

The object "camera" sends out a ray from the ray sensor. if the ray collides with anything that does not have the property named "bullet", the object "target" will snap to the position where the ray collided.
And because your guns are always tracking to the object "target" it will appear, and function as if the guns are always pointing to the center of the screen, wherever the object "camera" is looking.